/*
 * Copyright (c) 2015-2018, IGN France.
 * Copyright (c) 2018-2026, Giro3D team.
 * SPDX-License-Identifier: MIT
 */

import { LazPerf } from 'laz-perf';

import Fetcher from '../../utils/Fetcher';

export const DEFAULT_LAZPERF_PATH = 'https://cdn.jsdelivr.net/npm/laz-perf@0.0.7/lib';

let lazPerfPath = DEFAULT_LAZPERF_PATH;
let lazPerfWasmBinary: ArrayBuffer | null = null;

/**
 * Sets the path to the directory that contains the laz-perf library files.
 *
 * This must be set before instantiating any class that makes use of this library.
 *
 * For example, if the `laz-perf.wasm` file is served from
 * `<website>/public/wasm/laz-perf.wasm`, the path to configure is the following:
 * ```ts
 * setLazPerfPath('/public/wasm/');
 * ```
 *
 * Note: the default path to the laz-perf library is {@link DEFAULT_LAZPERF_PATH}.
 */
export function setLazPerfPath(path: string): void {
    lazPerfPath = path;
}

export function setLazPerfWasmBinary(wasmBinary: ArrayBuffer): void {
    lazPerfWasmBinary = wasmBinary;
}

/**
 * @internal
 */
export function getLazPerfPath(): string {
    return lazPerfPath;
}

let lazPerf: Promise<LazPerf> | undefined = undefined;

export function loadWasmBinary(): Promise<ArrayBuffer> {
    return Fetcher.arrayBuffer(lazPerfPath + '/laz-perf.wasm');
}

async function loadLazPerfFromWasmBinary(binary: ArrayBuffer): Promise<LazPerf> {
    return LazPerf.create({
        wasmBinary: binary,
    });
}

/**
 * Loads one instance of the LazPerf library.
 */
async function loadLazPerf(wasmPath: string): Promise<LazPerf> {
    // console.log('initializing laz-perf with path: ' + wasmPath);
    return LazPerf.create({
        locateFile: (file: string) => `${wasmPath}/${file}`,
    });
}

/**
 * @internal
 */
export function getLazPerf(): Promise<LazPerf> {
    if (!lazPerf) {
        if (lazPerfWasmBinary != null) {
            lazPerf = loadLazPerfFromWasmBinary(lazPerfWasmBinary);
        } else {
            lazPerf = loadLazPerf(lazPerfPath);
        }
    }

    return lazPerf;
}